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The levels, inclines and slopes are from ten to 

 twelve feet wide, with an average height of six and 

 a half feet, are substantially timbered where needed, 

 and are flanked by solid pillars of coal of as many as 

 forty yards in width which form a grand support to 

 the 'superincumbent mass, measuring at some points 

 600 and in others 1,800 feet to the surface. The in- 

 clines, levels and slopes are the great highways and 

 with the airways driven alongside them form the 

 lungs of the mine; similar wide pillars also bound the 

 airways or counter levels, and behind the pillars road- 

 ways are driven, off which the miners open up stalls 

 or rooms, out of which the coal is mined. In this pit 

 the system of working is called the "panel and stall." 

 The panels are limited areas of the seam which are 

 sub-divided into pillars and stalls which are worked 

 from twenty-five yards centres, and when the stall is 

 worked to the end of its limit or panel varying from 

 200 to 350 yards in length, there remain in the mine 

 solid coal pillars of fifteen yards in width on each 

 side of the empty space (or worked-out stalls) and 

 the result, generally is that from three-fifths to two- 

 thirds of the original coal seam is left standing in the 

 mine awaiting the time when the extreme limitations 

 of operations of the pit have been reached, and the 

 order is given to draw the pillars, the execution of 

 which commences at the farthest distance from the 

 pit (to the "rise" or "dip" of the seam according to 

 circumstances), the pillars are withdrawn, letting the 

 roof come down behind, so that the life of a pit is a 

 long and lingering one, and manv years elapse before 

 an extensive one is worked out. The "levels," while 

 they are graded systematically, follow the contour of 

 the seam transversely, as we would grade a road 

 round a hill side, and therefore the levels are not 

 straight. The workings off the main levels are sep- 

 arated by means of the inclines and slopes ^ of the 

 seam, which are driven in right lines, some inclines 

 running up from 1,000 to 1,500 yards. The coal is 

 brought from the stalls to the inclines in cars by 

 mules wherever they can be worked, and otherwise 

 by the pushers, who have also to keep the miners 

 supplied with emptv cars. The cars are let down 



